There are many known methods of using the heat of the earth, i.e., geothermal power, to produce electricity. Most methods, however, require expensive maintenance and are limited in that they produce environmental pollution, degrade the geothermal source and/or geographical location of the geothermal resource. Among the restraints that create the high costs of maintenance are the conditions of the geothermal resource, which often contains hydrochloric acid, sulphuric acid and/or nitric acid, all in the form of vapors or fumes that eat away at the materials used to harness the energy. A geothermal unit desired to last for an extended period of time typically includes a closed loop system, that is, a system that processes its internal media, usually water, from a gaseous state (steam) back to a liquid state in a continuing cycle. However, such a closed loop system has the problem of molecular mass growth of mineral or metallic matter that increases in volume over time. Although the water used in a closed system starts out inert, the carbon dioxide, and all minerals being removed, the continuing action of "molecular drag" of the water being forced through the system in its two basic states, water and steam, and enduring the many cycles of that transformation over time foments the environment under which this "molecular drag" takes place. When the molecular mass grows sufficiently, it becomes damaging to the working parts of the system and can be fatal to the turbine if it strikes the turbine blades at high pressure or high speed. It may also lock up the valves, gates and pumps of the power system.
Many methods use additional water that is pumped down into the geothermal source which is then heated by the geothermal source and either pumped back to the thermal jackets of the turbine boilers or returned of its own accord under pressure of contact with the geothermal source.
Conventional installations are costly and ponderous in size. Geothermal units also create environmental pollution by emitting gases that are brought to the surface, or by producing contaminated water that has been pumped from the geothermal source. The contaminated water is sometimes eliminated by forming surface ponds that contaminate the soil, or by diverting the runoff into ocean or waterways. In some systems, contaminated steam is dispersed into the atmosphere. Moreover, surface operations are highly noise polluting.
During the generation of electricity by coal or gas burning units, gas may be emitted and create "acid rain". This "acid rain" drifts with the prevailing winds and causes devastation to forests, rivers and the landscape. Similarly, for the average power plant, the area that must be cleared is very large. Additionally, there is a great deal of waste in power plants, such as steam turbines powered by gas, oil, or coal as most in use today require water streams of 500 or more gallons per minute to function, especially that use heat recovery generating systems (HRGSs). That water is usually dumped after use, typically downstream into a river or tributary at a temperature harmful to the ecosystem.
Waste is also generated by the continual usage of parts that must constantly be changed. These parts usually are discarded as they generally are not repairable. This creates yet another source of pollution. Of course, all fossil-fuel plants consume an irreplaceable resource, namely fossil fuel.
One of the more costly segments of conventional power installations is the manpower required to construct and operate the same. In particular, the electrical cable installations within the units are often subject to relatively high temperatures. Such environments lead to required changes of the wiring harness from time to time so as to keep the insulation from getting charred or brittle over time.
Additionally, because there is no harmonic synchronization between boiler and condensers, most power plants do not re-condense the steam to water, but rather discharge the steam. Those power plants that do recondense the steam to water have a myriad of pumps and valves that require a great amount of power for operation. The required power is often taken from what is generated thus lessening the amount of power available to be sold.
It can therefore be appreciated why most power systems are still not efficient and are still a pollution problem.
If power is to be made more affordable then it should also be made as safe as possible, non-polluting, immediately renewable, and reasonably limited in the amount of space and materials consumed. Moreover, it should be dependable for long periods of time and simple to supervise, manage and control.